Disposable device for treatment of infections of human limbs

ABSTRACT

A disposable device for treatment of infections of human limbs, particularly limbs having long bones susceptible to stabilization by intramedullary nailing. The device includes a tubular member made of a relatively rigid and biologically compatible material, having pores for impregnation with drugs or medicaments for infection treatment prior to or during insertion thereof in the stabilization site. An assembly for treatment of human limb infections including such device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of application Ser. No. 11/884,663 filedAug. 20, 2007 and which is currently pending, the disclosure of which isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention is applicable in the technical field of surgicalinstruments, and particularly relates to a disposable device fortreatment of infections of human limbs, more specifically limbs havinglong bones susceptible to stabilization by intramedullary nails.

BACKGROUND OF THE INVENTION

Stabilization of long bones of the human body, following fractures,malformations or similar pathologic situations is known to be attainedby using well-known devices such as intramedullary nails, consisting ofmore or less curved hollow or solid metal rods, which are fitted intothe intramedullary cavity of the bones to be stabilized and are anchoredto the stumps or parts to be stabilized by transverse-pins or screws,typically in the distal and proximal region of the limb. Once thefracture has been stabilized and fixed, the pins are removed and thenail is extracted from the medullary canal.

One problem associated to such treatment, in addition to theinvasiveness of the implantation procedure, is the establishment ofinfection foci, which may locally develop due to the incompatibility ofmetal with the spongy medullary tissue and due to the bacteria thatnormally come in contact with the implantation site.

In order to minimize such drawbacks, it is highly recommended that theimplantation of the above devices occurs in wholly sterile conditions,and that the relevant part is treated with substances adapted to preventand/or treat such infections.

In an attempt to at least partly obviate the above drawbacks, solutionshave been developed to allow in situ application of the abovesubstances, alone or added to bone cement.

The U.S. Pat. No. 4,863,444 discloses a carrier shaped like a stickthrough which an antibiotic could be distributed. The stick, due to itselongated configuration, can be inserted into the channel providedthrough the skin and the soft tissues for the accommodation of anexternal fixture comprising a screw or a nail introduced into the bone.

A solution is known in which a cover for the stabilizer device is madeby using molds at the factory or directly at the surgical siteimmediately before implantation of such device.

This solution also has several apparent drawbacks.

First, it is a substantially manual solution, which requires specialskills from the operator, who has to be properly trained therefor. Suchan operation further involves many processing scraps, thereby causing ahigh material waste and an increase of the overall processing costs.

The thus covered device is also exposed for a sufficiently long time toair and to contact with foreign material, which involves a high risk ofattack by bacteria and contaminants.

Furthermore, the covered device which comes out of the mold will exhibitmany burrs along its longitudinal extension, which will have to beremoved for proper positioning, thereby involving longer implantationtimes and consequent discomfort for the patient.

A further aspect of the invention relates to the need of temporarilyreplacing an intramedullary nail for one of several different reasons,such as recidivation or dislocation of the implant, normally followed bysurgical site infections.

In these situations, the existing intramedullary nail has to be removedand the implant site has to be treated before insertion of the new nail.In the meantime, the geometry of the site shall be maintained unchanged,to prevent shortening and deformation of tissues, by providing a spacerdevice which can also prevent and/or treat the infections due to the oldand new implant.

SUMMARY OF THE INVENTION

It is a main object of the present invention to overcome the abovementioned drawbacks by providing a device for infection treatment thatexhibits high efficiency and cost effectiveness. A particular object isto provide a ready-to-use device for treatment of infections, whichavoids the use of skilled personnel.

A further object is to provide a device for treatment of infections thatallows to reduce the time of exposure thereof to the environment andassures highly sterile conditions.

Another object is to provide a device for treatment of infections thatallows an optimized use of materials.

Yet another object is to provide a device for treatment of infectionsthat allows fast removal of the cover.

These objects, as well as other objects that will be more apparenthereafter, are fulfilled by a disposable device according to an aspectof the present invention.

This particular arrangement of the invention provides a ready-to-usedevice for treatment of infections, while avoiding the need of skilledpersonnel to fabricate it.

Furthermore, this particular arrangement of the invention allows anoptimized use of materials, and wholly eliminates processing scraps,while reducing the time required for fitting such cover onto the nail.

Preferably, the device for treatment of infections may be made of amaterial selected from the group including bone cements and reabsorbableor biodegradable bone cements. Thus, the device will be biologicallycompatible with the limb to be treated.

This tubular member may be suitably hollow, to allow fitting thereofonto an intramedullary nail.

Thanks to this feature, the device of the invention allows an optimizeduse of the base material, and increases cost-effectiveness.

In accordance with a further aspect of the invention, there is providedan assembly for treatment of infections of human limbs according whichcomprises a sterile enclosure or blister, which is designed to contain atubular member as described above.

This particular arrangement of the invention provides a device fortreatment of infections which assures high sterility.

According to one aspect, a disposable device for treatment of infectionsof human limbs is provided comprising an intramedullary nail suitablefor stabilization of human limbs with a distal region and a proximalregion, and a tubular member comprised of a relatively rigid andbiologically compatible material and configured to at least partiallycover said intramedullary nail, said material comprising at least one ofa porous or spongy material, said tubular member having a proximalregion and a distal region and pores integrated arbitrarily throughoutthe material of said tubular member, said material of the tubular memberbeing impregnated with drugs or medicaments for treatment of infections,prior to or during insertion thereof in the stabilization site.

According to another aspect, a disposable device for treatment ofinfections of human limbs is provided comprising a tubular member madeof a relatively rigid and biologically compatible material, saidmaterial comprising at least one of a porous or spongy material, saidtubular member having pores integrated arbitrarily throughout thematerial of said tubular member, wherein the material of said tubularmember is configured to be impregnated with drugs or medicaments fortreatment of infections, prior to or during insertion thereof in thestabilization site, said pores being disposed in a casual pattern andlocated in the outer surface and/or in the inner part of said tubularmember, wherein said tubular member is internally associated with astable reinforcement core made of a relatively rigid metal or non-metalmaterial, whereby said device forms an intramedullary nail suitable forstabilization of said human limbs.

According to yet another aspect, a device providing an intramedullarynail for treatment of infections of human limbs is provided comprising astable reinforcement core made of a relatively rigid metal or non-metalmaterial, said stable reinforcement core having an external surface, anda tubular member made of a biologically compatible material, saidmaterial comprising at least one of a porous or spongy material, saidtubular member being intimately adherent to the external surface of saidstable reinforcement core, said material of the tubular member includingpores configured to be impregnated with drugs or medicaments fortreatment of infections, prior to or during insertion thereof in thestabilization site; and said pores being integrated arbitrarilythroughout the material of said tubular member and disposed in a casualpattern and located in the outer surface and/or in the inner part ofsaid tubular member.

According to yet another aspect, a method for providing a device fortreatment of infections of human limbs is provided comprising the stepsof providing a solution comprised of a base material composed of apolymer or bone-cement material with an organic or aqueous solvent inwhich the concentration of the base material versus the solvent is about1% (w/w) to about 75% (w/w), adding a drug or other medicament in thesolution at a concentration versus the polymer of about 5% (w/w) toabout 65% (w/w), homogenizing the solution, applying the solution to anintramedullary nail through immersion of the intramedullary nail in thesolution and emersion of the intramedullary nail, waiting about 10-60minutes, and repeating the steps of applying and waiting alternativelyat least other two times.

Further features and advantages of the invention will be more apparentfrom the detailed description of a preferred, non-exclusive embodimentof a disposable device according to the invention, which is described byway of non-limiting example with the help of the annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of one embodiment of the device according to theinvention;

FIG. 2a is a sectioned view of the device as shown in FIG. 1, takenalong a plane IIa-IIa

FIG. 2b is a sectioned view of the device as shown in FIG. 1, takenalong a plane IIb-IIb;

FIG. 3 is a side view of a further embodiment of the device according tothe invention;

FIG. 3a is a sectioned view of the device as shown in FIG. 3, takenalong a plane IIIa-IIIa;

FIG. 3b is a sectioned view of the device as shown in FIG. 3, takenalong a plane IIIb-IIIb;

FIG. 4 is an axonometric view of another configuration of the deviceaccording to the invention;

FIG. 4a is a sectioned view of the device as shown in FIG. 4, takenalong a plane IVa-IVa;

FIG. 4b is a sectioned view of the device as shown in FIG. 4, takenalong a plane IVb-IVb;

FIG. 5 is a side view of a further embodiment of the device of FIG. 4;

FIG. 5a is a sectioned view of the device as shown in FIG. 5, takenalong a plane Va-Va;

FIG. 6 is a side view of another configuration of the device accordingto the invention;

FIG. 7 is a further side view of the device as shown in FIG. 6;

FIG. 8a is a sectioned view of the device as shown in FIG. 7, takenalong a plane VIIIa-VIIIa;

FIG. 8b is a sectioned view of the device as shown in FIG. 7, takenalong a plane VIIIb-VIIIb;

FIG. 8c is an enlarged view of a detail of FIG. 8 b;

FIG. 9 is a side view of the assembly according to the invention;

FIG. 10 is a further side view of the assembly according to theinvention;

FIG. 11 is a side view of a further embodiment of the device of FIG. 1.

FIG. 12 is a schematic partial sectional view of a version of the deviceaccording to the invention;

FIG. 13 is an exemplary optical microscope view of a device according toan aspect of the present invention;

FIG. 14 is an exemplary flow chart of a method of providing a deviceaccording to an aspect of the present invention; and

FIG. 15 is a schematic partial sectional view of another embodiment ofthe device according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the above figures, a device of the invention, generallydenoted by numeral 1, is of the disposable type and will be particularlydesigned for stabilization of limbs having long bones by intramedullarynailing. Intramedullary nails or rods are used to align and stabilizefractures and are inserted longitudinally into the medullary canal inthe center of the long bones of the extremities (e.g. femur or tibia).

The device includes a tubular member 2 made of a biologically compatiblematerial, which may also be of the reabsorbable or biodegradable type.

The device includes a tubular member 2 is made of a biologicallycompatible material, preferably selected from bone cements.

In a version of the invention, the compatible material of which thetubular member 2 is made is rigid.

The material of which is made the tubular member 2 may be insoluble, andtherefore permanent, or soluble, and therefore may be reabsorbed in thehuman body.

The insoluble material may be obtained by a dispersion of polymers ofpolymethylmethacrylate (PMMA) and/or PMMA esters, such asbutylmethacrylate, etcetera, and/or co-polymers, such as thePMMA-Polymethylstyrene, etcetera, in an organic solvent as, for example,methylmethacrylate monomer, MMA, chloroform, or other organic solventbeing suitable to melt the PMMA and/or the PMMA esters and/orco-polymers, in which possible drugs or other medicaments may be added.The solvent may be also water.

The soluble material, instead, may be obtained by a dispersion ofpolymers soluble in the human body, such as polyglycolic acid (PGA),polylactic acid (PLA), copolymers of polyglycolic acid and polylacticacid (PGA-PLA), copolymers of L polylactic acid and polyglycolic acid(PLLA co PGA), copolymers of L-D-polylactic acid and trimethylenecarbonate (PLDA co TMC), polyvinylpyrrolidone (PVP) derivates,polyvinylchloride (PVC), amide or cellulose derivates, etc. and anorganic solvent, such as methylmethacrylate, chloroform, or otherorganic solvent being suitable to melt the above-mentioned polymers, inwhich possible drugs or other medicaments may be added. The solvent maybe also water.

The insoluble and soluble materials are applicable on an intramedullarynail C, after their dispersion or solubilisation in suitable organic,inorganic and/or aqueous solvents.

The above mentioned materials may comprise all optically active isomersor racemic forms.

According to one embodiment, the tubular member 2 may be comprised of amaterial comprising at least a porous or spongy material.

According to an aspect of the present invention, the tubular member 2has pores 2′ configured to be impregnated with drugs or medicaments fortreatment of infections, such as antibiotics, growth promoters,anti-inflammatory and/or antitumor drugs.

In the present specification, the term “pores” means: a small space or adistance from the molecules that compose a body, specifically, thetubular member 2.

In accordance with a first version of the invention, the tubular member2 has a central axial cavity 3 for the passage of an intramedullary nailC that is at least partially covered by the tubular member 2 itself.

In this first version, the tubular member 2 is obtained by the reactionof the above-mentioned substances and, when inserted in thestabilization site, the reaction has already been concluded: thematerial is already polymerized and it is porous and therefore used fordrugs or other medicaments release.

The pores 2′ have a micrometrical dimension and are advantageouslynaturally obtained by the polymerization reaction. This polymerizationreaction starts at room pressure and the air and vapors of the monomeror of the other type of organic solvent, searching for an escape way,create the porosity.

When the solvent evaporates, it creates in the material of the tubularmember 2 some escape paths that are the pores 2′ from which, in a secondmoment, the drugs or medicaments are released.

Due to the fact that the impregnation of the tubular member 2 is enabledby way of pores 2′ distributed on the tubular member 2 itself, the timeof impregnation may be controlled. For example, impregnation may occurat various desired times, such as prior to or during insertion into astabilization site, or even prior to packaging of the device 1.

The pores 2′ are present on the external surface S and into the tubularmember 2. The pores 2′ may be interconnected and are disposed in acasual pattern of distribution. The pores 2′ are natural and of amicrometrical size. Preferably, the pores 2′ are not through-pores,i.e., they do not form a direct, unimpeded path between the outer andinner surfaces of the tubular member 2.

In a version of the invention, the pores 2′ have a size of about 100-200micrometers. In this case, the pores 2′ are large and may be produced,for example, by the presence of water dispersed in the material of thetubular member 2, i.e. the cement mass. The water is insoluble in thefluid cement mass and therefore it generates a phase separation. Duringthe cement polymerization, the phase separation generates a solid cementmatrix in which the pores 2′ or micro-channels are displaced.

In a version of the invention, the pores 2′ may have a dimension ofabout 1-100 micrometers in order to avoid the bone tissue growth throughthem, and preferably of about 100 micron.

The pores 2′, and/or the tubular member 2 through the pores 2′, may beimpregnated with drugs or medicaments for treatment of infections. Thepores 2′, which are not necessarily through-pores, enable the retentionof the drugs or medicaments within the structure of the tubular member2, and the release of these substances in the external environment, forexample the bone. The pores 2′ are not in direct communication with thecentral cavity 3 or with the internal nail or core of the device 1. Infact the pores 2′ are blocked or sealed by the nail or the core insertedinto the tubular member. For example, the pores 2′ act like littletanks, to retain the above-indicated drugs or medicaments, which theyrelease during the time when they are in contact with the implantationsite to be treated.

In one version, the drugs or medicament may be in a dry form in order tobe mixed with the material of which the tubular member 2 is made. Inthis way, these substances are directly contained in the tubular member2 and the pores 2′ provide a path for the release of these substancesfrom the inside the tubular member 2 itself to the outside.

Alternatively, the tubular member 2 may not directly contain theabove-indicated drugs and medicaments but, being porous or spongy thanksto the pores 2′, it is suitable for being soaked in these substancesthat are in a fluid form at the moment of the implantation of the device1 in the patient.

In a version of the invention, the tubular member 2 may be quicklyremoved from the nail C, thereby allowing simple replacement of thelatter after proper sterilization.

Furthermore, the tubular member 2 may comprise connection means 4 foranchorage thereof to the nail C, which connections means preferablycomprise an adhesive material 5 interacting with the member 2 and theintramedullary nail C on which it is fitted. Conveniently, the material5 may be uncured bone cement, designed to partly cover both the tubularmember 2 and the intramedullary nail C on which it is fitted andpreferably laid or injected in at least one through cavity 6 of thetubular member 2.

In accordance with another version of the invention, as showed in FIG.11, the tubular member 2 may be obtained by applying, on theintramedullary nail C, a solution formed by a combination of bone-cementand/or other polymer material and chloroform or one of theabove-mentioned organic solvents or water. When the chloroform or theorganic solvent or water evaporates, a thin layer of porous bone-cementor polymer material remains on the intramedullary nail C. Theevaporation and/or the polymerization of chloroform or the organicsolvent or water determines the deposition of a solidified layer ofbone-cement or polymer material, that constitutes the tubular member 2,and at the same time the formation, as explained above, of pores 2′ thatcan be at most interconnected and distributed in a casual and arbitrarymanner. The pores 2′ may have a size of about 100-200 micrometers.

The tubular member 2 has a thickness which dimension depends on thenumber of applications of the above-indicated solution. The thickness ofthe tubular member 2 may vary from about 10 micrometers to 1000micrometers.

When the thickness of the tubular member 2 is about 10 micrometers, itrealise a sort of barrier against the bone tissue growth. This isparticularly useful for Titanium nails—more than for hard steel AISI316L or Cobalt-Chrome alloys nails—because the tubular member 2 createsa barrier against the close encapsulation of the bone tissue on the nailwhich makes difficult the removal of the nail itself.

The thickness of the tubular member of about 100-400 micrometers isuseful for drugs or other medicaments delivery; if the thicknessincreases over 600 micrometers, the drug delivery period will be longeras there is a bigger quantity of drug or other medicaments incorporatedin the tubular member 2.

However, if the tubular member has a thickness greater than 250 micron,the size of the intramedullary nail varies: therefore, in a version ofthe invention it is avoided.

As above explained, the pores 2′ may be impregnated with drugs ormedicaments for treatment of infections: the drugs or medicament may bein a dry form in order to be mixed with the material of which is madethe tubular member 2. In this way, these substances are directlycontained in the tubular member 2 and the pores 2′ provide a path forthe release of these substances from the inside the tubular member 2itself.

Alternatively the tubular member 2 does not contain directly theabove-indicated drugs and medicaments but, being porous or spongy thanksto the pores 2′, is suitable for being soaked by these substances thatare in a fluid form at the moment of the implantation of the device 1 inthe patient.

In a version of the present invention, the tubular member 2 comprises awall, of the above-indicated materials, applied by at least oneimmersion of the intramedullary nail C in the above-solutions. In otherversions, the above-solution can be painted, and/or sprayed, and/orimpregnated, and/or embedded, onto the intramedullary nail C, thuscreating the wall comprised in the tubular member 2. The wall could havevarious thicknesses depending on the thickness of the applied material,the number of applications and the time of application.

The pores 2′ of the present invention, obtained as explained above, aredisposed and integrated in a very casual and arbitrary pattern andmanner throughout the tubular member 2, e.g., on the outer and innersurfaces as well as internally throughout and within the tubular member2.

The pores 2′, thanks to the fact that are formed naturally during thetubular member 2 formation, do not require a specific realizing orcreation step and therefore makes the production of the device 1 easier,quicker and cheaper, unlike known devices that comprise tubular membersin which holes or ducts have to be predisposed and operatively createdor obtained in the device itself.

In accordance with a version of the invention, the tubular member 2 maybe substantially continuous and have a predetermined length, preferablycorresponding at least to the distance between the holes F and F′ in thedistal and proximal regions D, P respectively of the intramedullary nailC, as shown in FIG. 1. Thanks to this feature of the invention, thetubular member 2 may be coupled to the intramedullary nail C in a stillmore stable and less invasive manner.

Advantageously, as particularly shown in FIG. 3, in addition to thecavity 6, a hole 7 may be provided in the proximal region P′ or distalregion D′ of the member 2 for the passage of corresponding screws foranchorage of the intramedullary nail C, not shown in the figures. Thescrews will firmly secure the nail C, with the device 1 thereon, to thebone to be stabilized, to increase the stability of the treatment. Thisway of securing of the nail C, and of the tubular member 2, to the boneto be stabilized, prevent the utilization of bone-cement that, whenfinally cured, raises high reaction temperatures and produces monomersthat have the disadvantageous biological effect on the bone, killing thebone tissue.

According to a version of the invention, showed in FIGS. 4 and 5, thetubular member 2 may be a strip 8 of base material, which is wound in asubstantially helical shape. Suitably, the turns 9 of such helical shapemay be equally spaced, to define a through cavity 10, also having asubstantially helical shape.

Preferably, the strip 8 may include an inner and/or outer reinforcementlayer 11, made from a woven or non woven fibrous material, preferably ofthe mesh type.

According to a version of the invention, showed in FIGS. 6-8, thetubular member 2 may be provided with a stable reinforcement core 12,which is made of a relatively rigid metal or non-metal material, toactually define, as a whole, a spacer assembly.

Advantageously, the core 12 may have an irregular outer surface 13,defining an externally threaded anchorage area Z for the member 2.

According to another embodiment, the above-mentioned solution forobtaining a tubular member 2 may be painted onto the core 12, and may bejoined to the core 12 due to adhesion (e.g., due to mechanical and/orchemical-physical properties). For example, the mechanical adhesion maybe due to irregularity of the core's surface, such as microcavities orundercuts 13, into which the tubular member's material enters. Anexample of the chemical-physical adhesion may be due to the attractioninduced by molecular weak forces, for example Van der Waals forces,exerted between the different materials (e.g., of the tubular member 2and of the reinforcement core 12).

Furthermore, a gripping member 14, preferably a ring, may be provided atthe proximal end of the reinforcement core 12, to facilitate removal ofthe spacer assembly.

Here again the tubular member 2 may be impregnated with drugs ormedicaments for treatment of infections, such as antibiotics, growthpromoters, anti-inflammatory and/or antitumor drugs. Impregnation mayoccur prior to packaging of the device or up on insertion thereofon-site by the surgeon, as explained above.

As shown in FIGS. 9 and 10, the device 1 comprises a sterile enclosureor blister 15 in order to form an assembly 20 for treatment ofinfections of human limbs, particularly limbs having long bonessusceptible to stabilization by intramedullary nail, and to assure thehighest sterility and guarantee preservation conditions beforeinstallation.

This particular configuration of the invention provides a ready-to-usedevice for treatment of infections, which avoids the use of skilledpersonnel. The device further optimizes the use of materials, byconsiderably reducing processing scraps.

Finally, the construction of the above assembly 20 provides a device fortreatment of infections that allows reducing the time of exposurethereof to the environment and assures highly sterile conditions.

The device of this invention is susceptible of a number of modificationsand changes falling within the scope disclosed in the appended claims.All the details thereof may be replaced by other technically equivalentparts, and the materials may vary depending on different needs, withoutdeparture from the scope of the invention.

FIG. 12 discloses a schematic sectional view of a version of the tubularmember 2 deposited by painting over the intramedullary nail C. Insidethe tubular member 2 some spherules of antibiotic G could be seen.

In a version in which the above-solution is painted onto theintramedullary nail C or onto a reinforcement core, the tubular member(of such a painted version) may be joined to the nail C and/or to areinforcement core thanks to, e.g., an adhesive phenomenon. Thisadhesive phenomenon may have, e.g., mechanical and/or alsochemical-physical properties. For example, the mechanical adhesion maybe due to irregularity of the nail's surface (e.g., as shown in FIG.15), such as microcavities or undercuts 1501, into which the tubularmember's material 2 enters. An example of the chemical-physical adhesionmay be due to the attraction induced by molecular weak forces, forexample Van der Waals forces, exerted between different materials (e.g.,the material of the tubular member and of the nail C).

FIG. 13 is an optical micrograph 2 depicting a view of a version of thetubular member 2 under magnification in which the pores 2′ and thespherules of antibiotic G could be seen. This image has a 20×magnification. This image was taken about 0.1 mm below the surface ofthe tubular member.

FIG. 14 outlines exemplary method steps of a version of the process ofapplying the material of the tubular member onto the intramedullary nailC. This method comprises a step 1201 of providing a solution comprisedof a polymer and/or bone-cement with a solvent in which theconcentration of polymer and/or bone cement in the solvent is about 1%(w/w) to about 75% (w/w), a step 1203 of adding an antibiotic in thesolution at a concentration in the polymer of about 5% (w/w) to about65% (w/w), a step 1205 of homogenizing the solution, a step 1207 ofapplying the solution to an intramedullary nail through immersion of theintramedullary nail in the solution of phase 1205 and emersion of theintramedullary nail, a step 1209 of waiting about 10-60 minutes, a step1211 of repeating phase 1207 and 1209 alternatively at least other twotimes. The method further comprises a step 1213 of evaporation of thesolvent in air for about 24 hours to eliminate the most of the solventitself, and a step 1215 of drying for about 5 hours at about 70° C. theintramedullary nail to completely eliminate the residual solvent byevaporation and/or polymerization thus creating the tubular member andthe pores 2′.

The rate of immersion of the intramedullary nail may vary between about1 cm/min and about 60 cm/min and preferably it is about 30 cm/min; therate of emersion may vary between about 1 cm/min and about 60 cm/min andpreferably of about 5 cm/min.

Preferably the concentration of polymer and/or bone cement in thesolvent is about 12% (w/w) to about 38% (w/w) and more preferably ofabout 25% (w/w); preferably the concentration of an antibiotic, forexample gentamicin sulfate, is about 7% (w/w) to about 23% (w/w) andmore preferably of about 15% (w/w). Preferably the time to step 1209 is30 min and the number of repetition of steps 1207 and 1209 alternativelyis about three more times.

In a version of the invention, at every subsequent immersion, theintramedullary nail is overturned, in order to have a uniform cover ofthe tubular member 2 on the intramedullary nail.

Each centimeter of intramedullary nail is covered by an amount of about15 mg to about 60 mg of tubular member 2, and preferably by about 35 mg.

While the device has been described with particular reference to theaccompanying figures, the numerals referred to in the disclosure andclaims are only used for the sake of a better intelligibility of theinvention and shall not be intended to limit the claimed scope in anymanner.

The invention claimed is:
 1. A disposable device for treatment ofinfections of human limbs, comprising: an intramedullary nail suitablefor stabilization of human limbs the intramedullary nail with a distalregion and a proximal region, wherein said intramedullary nail comprisestwo holes including a first hole located in the distal region and asecond hole located in the proximal region; and a tubular membercomprised of a relatively rigid and biologically compatible material andconfigured to at least partially cover said intramedullary nail, whereinsaid tubular member is substantially continuous and has a predeterminedlength corresponding to at least the distance between said first andsecond holes, said material comprising at least one of a porous orspongy material, said tubular member having a proximal region and adistal region and non-through pores integrated arbitrarily throughoutthe material of said tubular member, the tubular member including anoval-shaped hole in one of the proximal region or the distal region ofsaid tubular member transverse to a longitudinal axis of the tubularmember and for passage of corresponding screws for anchorage of thetubular member and the intramedullary nail to a bone to be stabilized,and said non-through pores of the material of the tubular member beingimpregnated with drugs or medicaments for treatment of infections, andbeing of a size to avoid bone growth through them.
 2. The device asclaimed in claim 1, wherein said material is selected from at least oneof: the group consisting of bone cements and/or reabsorbable orbiodegradable bone cements, and/or a dispersion of polymers ofpolymethylmethacrylate (PMMA) and/or PMMA esters, includingbutylmethacrylate, and/or co-polymers, including thePMMA-Polymethylstyrene, in an organic solvent or water; and/or adispersion of polymers selected from the group consisting ofpolyglycolic acid (PGA), polylactic acid (PLA), L polylactic acid, L-Dpolylactic acid, trimethylene carbonate, polyvinylpyrrolidone (PVP)derivates, polyvinylchloride (PVC), amide or cellulose derivates and/ortheir isomers or racemic forms, and copolymers thereof and an organicsolvent or water.
 3. A device as claimed in claim 1, wherein saidtubular member has a central cavity for passage of the intramedullarynail.
 4. The device as claimed in claim 1, wherein said tubular membercomprises a thickness of about 10-1000 micron.
 5. An assembly fortreatment of infections of human limbs, susceptible to stabilization byintramedullary nailing, comprising a sterile packaging blister whichcontains the device as claimed in claim
 1. 6. The device as claimed inclaim 1, wherein the pores have a dimension of about 1 to 100micrometers.
 7. The device as claimed in claim 1, wherein the pores havea dimension of about 100 microns.